SO2 Removal Activity and its Regeneration of Polyacrilonitrile Based Active Carbon Fiber (PAN-ACF )

Abstract

SO, removal activity of a commercially PAN-ACF, FE-300 was examined at 100 °C in its repeated use by regenerating it at a temperature range of 400-1000 °C, using model flue gas containing 1000 ppm SO, . The particular ACF showed an excellent removal activity after the heat treatment at 800 °C (FE-300-800) providing a breakthrough time of 5.1 h. However its activity was so much reduced in the second successive runs to be 50% of the first run, when its ACF was regenerated before the successive are at 500 °C, where adsorbed SO₂ was completely recovered.
High temp erature of 800 °C regenerated more the activity, although the breakthrough time was still 4.5 h in the second run, and decreased steadily in the successive runs. Such regeneration provoked a large carbon loss by evolving CO, and CO after the recovery of SO₂.
The activity was almost completely regenerated when the ACF was treated with NH 3 at 500 °C after the complete recovery of SO₂. NO was found reduced with NH₃ at 500 °C over the ACF after the recovery of SO₂, exhibiting a conversion of 60% recovery of SO₂ adsorption ability. Reduction with NH₃ for the recovery of SO, adsorption led to no carbon loss at the regeneration. The role of oxygen functional groups introduced by oxidative adsorption and desorption of SO₂ are discussed for the oxidative adsorption of SO2 in the successive runs.