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활성탄 흡착탑에서 휘발성 유기화합물의 열 재생 특성(I):흡착단계

The Thermal Regeneration Characteristics of Volatile Organic Compounds on an Activated Carbon Bed(I): Adsorption Step

황계순 최대기 공성용

Hwang KS Choi* DK Gong SY

HWAHAK KONGHAK, April 1998, 36(2), 159-168(10), NONE

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Abstract

활성탄 흡착탑에서 메틸렌 클로라이드 증기의 흡착단계의 실험을 수행하였고 모델식을 이용하여 이를 해석하였다. 흡착단계의 농도와 온도 곡선을 계산하기 위하여 비평형, 비등온, 비단열 특성을 고려한 수학적인 모델식을 개발하였다. 흡착 파과실험을 수행하여 흡착 파과곡선에 대한 여러 조작 변수들의 영향을 조사하였으며, 선형 구동력 물질전달 속도식을 가정한 본 모델식이 실험결과를 잘 예측할 수 있다는 것을 확인하였다. 농도 곡선과 온도 곡선에 대한 열 전달계수와 물질 전달계수의 영향을 조사하였다. 총괄 열 전달 속도는 비 정상상태 영역에서는 칼럼벽과 대기와의 열 전달계수에 의해 제어되고, 정상상태 영역에서는 기상과 칼럼벽 사이의 열 전달계수에 의해 제어되는 것으로 나타났으며, 물질 전달속도는 표면 확산이 율속 단계인 것으로 나타났다. 또한, 본 시스템에서는 흡착 파과곡선이 흡착탑의 초기 온도에 영향을 받지 않는 것으로 나타났으므로, TSA 싸이클과 같은 싸이클릭 운전시에 냉각 단계를 생략해도 무방하다고 볼 수 있다.

The experimental and theoretical study was carried out for the adsorption of methylene chloride vapor on a activated carbon bed. A nonequilibrium, nonisothermal, and nonadiabatic mathematical model was developed to calculate the concentration and temperature profiles. A linear driving force mass-transfer model was found to be acceptable fit to the experimental data. The effects of operation variables, such as initial bed temperature, feed concentration etc., were investigated. Also, the effects of heat and mass transfer coefficients on the temperature and the concentration curve were studied. The overall heat transfer rate was controlled by the heat transfer between gas phase and bed wall. h_w, at unsteady state, while after reaching the steady state, heat transfer between wall and ambient, U_a, was rate controlling step. But the heat transfer coefficient between adsorbent and gas phase, h_s, had little effect on the temperature curves. It was also founded that mass transfer was limited by the surface diffusion. The cooling step followed by hot purge regeneration step in the TSA cycle might be omitted because the breakthrough curve of this system was not affected by the initial bed temperature.

Keywords

Methylene Chloride Activated Carbon Adsorption Thermal Regeneration Breakthrough Curve Linear Driving Force

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