Perfect removal of SOx, NOx, NH3 and dioxin over activated carbon fiber

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A flue gas treatment which consisted of switching two steps : removal of S0_2 and regeneration of adsorption ability, using a pitch based activated carbon fiber of very large surface area (ACF), was proposed to allow the continuous removal of S0_2 in flue gas with limited humidity at 50-70℃. Removal of S0_2 at 60-70℃ and regeneration at 30℃ with humid air without S0_2 were found successful to design a switching procedure. Higher temperature of regeneration required more time, although a small difference of two temperatures may be easy for control. The second procedure which removed S0_2 successively at two different temperatures was found also possible although the period of removal at a higher temperature was rather short. This procedure relies on the fact that the amount of adsorbed H_2S0_4 on ACF under stationary conditions was smaller at a lower temperature when sufficient amount of ACF was loaded. In both cases, the regeneration to elute out ad. H_2S0_4 over ACF is the rate determining. It is found by TPD that the regeneration at 30℃ and 70℃ eluted preferentially two H_2S0_4 species over the ACF surface which evolved at lower and higher temperatures, respectively. Adsorbed H_2S0_4 located in the pore which is easily reduced to evolve at a lower temperature in TPD procedure is eluted first at 30℃ since H_20 vapor can get into the pore at the temperature. In contrast, adsorbed H_2S0_4 located on the outer surface of ACF was preferably eluted out at 70℃. Such H_2S0_4 is away from the reactive ACF surface to be reduced to evolve at a higher temperature in TPD.