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Language: korean

Conflict of Interest: In relation to this article, we declare that there is no conflict of interest.

Publication history: Received January 5, 2004
Accepted May 7, 2004

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/bync/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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기체-액체 향류흐름 유동층에서 유동입자의 분산 거동해석

Analysis of Dispersion Behavior of Fluidized Particles in Gas-Liquid Countercurrent Fluidized Beds

손성모 김현태 강석환 강용^† 김상돈¹

Sung Mo Son Hyun Tae Kim Suk Hwan Kang Yong Kang^† Sang Done Kim¹

충남대학교 화학공학과, 305-764 대전시 유성구 궁동 220 ¹한국과학기술원 생명화공과, 305-701 대전시 유성구 구성동 373-1

School of Chemical Engineering, Chungnam National University, 220, Gung-dong, Yuseong-gu, Daejeon 305-764, Korea ¹Departement of Chemical and Biomolecular Engineering, KAIST, 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701, Korea

Korean Chemical Engineering Research, June 2004, 42(3), 332-337(6), NONE Epub 12 July 2004

Abstract

직경이 0.152 m이고 높이가 2.5 m인 기체-액체 향류흐름 유동층에서 유동입자의 분산 거동을 고찰하였다. 기체-액체 향류흐름 유동층에서 유동 입자의 흐름은 매우 불규칙적이기 때문에 입자의 분산 흐름 거동을 해석하는데 확률론적(stochastic)방법을 사용하였다. 압력 강하 및 요동(fluctuations)의 변동은 계단 함수로서 기체의 유속을 변화시킨 후 시간의 흐름에 따라 압력 변동을 측정하여 결정하였다. 입자의 분산 거동은 유동층이 최초 정상상태에서 기체의 유속이 단계함수로 변하여, 최종 정상 상태에 도달할 때까지 불균일 팽창과 균일 팽창 상태의 두 가지 상태로 분류 할 수 있었다. 유동층 내부의 일정 시험 영역에서 입자의 분산 계수, 요동 빈도수는 액체 또는 기체 유속의 증가에 따라 증가하였다. 폴리에틸렌과 같이 상대적으로 밀도가 큰 입자 유동층에서의 입자 분산 계수와 요동 빈도수가 폴리프로필렌과 같이 상대적으로 밀도가 작은 입자의 경우보다 크게 나타났다. 기체-액체 향류 흐름 유동층에서 입자의 분산 계수와 요동빈도수는 무차원군의 상관식으로 나타낼 수 있었다.

Dispersion behaviors of fluidized particles have been investigated in a gas-liquid countercurrent fluidized bed of 0.152 m ID and 2. 5m in height. Since the dispersion flow of particles is highly irregular, stochastic analysis has been employed to analyze the behavior of dispersion characteristics. Pressure drop fluctuations have been measured and analyzed with the variation of time after change of the gas flow rate as a step function. Effects of gas and liquid velocities and particle kind (density) on the dispersion coefficient, fluctuating frequency and exiting rate of particles from the test section have been determined. It has been found that the dispersion behavior of particles can be classified into two states, heterogeneous and homogeneous_x000D_ expansion states, before it finally reached a new steady state. The dispersion coefficient and fluctuating frequency of particles increase with increasing gas or liquid velocity. The values of DP and F in the beds of relatively higher density particles(PE) are higher than those of relatively lower density particles(PP). The values of D_P and F have been well correlated in terms of dimensionless groups.

Keywords

Gas-Liquid Countercurrent Three Phase Fluidized Bed Particle Dispersion Stochastic Analysis

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