Removal of SO2 by activated carbon fibers in the presence of O2 and H2O

This work describes the potential capability of activated carbon fibers (ACFs) in continuously removing SO2 from inert atmosphere without requiring further regeneration. A tubular reactor packed with ACF was used to study the conversion of SO2 into H2SO4 in the presence of O-2 and H2O with varying concentrations of SO2 (3000-10,000 ppm), O-2 (10-20%), and H2O (10-70%) and temperatures (313-348 K). The experiments were carried out on two precursors (viscose rayon and phenolic resin) based ACFs. The breakthrough data revealed that the steady-state SO2 concentration levels at the reactor exit increased with increasing inlet SO2 concentration and decreased with increasing concentration levels of O-2 as well as H2O. Increase in the reaction temperature was found to moderately enhance the steady-state exit concentration levels of SO2. The viscose rayon-based ACF exhibited higher SO2 removal activity in comparison to the phenolic resin-based ACF. A mathematical model was developed to predict the gas concentration profiles in the reactor, incorporating the mass transfer in the bed as well as within the ACF pores, along with the surface reactions on the ACF. The model predictions agreed reasonably well with the data. (C) 2005 Elsevier Ltd. All rights reserved.