K. Tsuji et I. Shiraishi, COMBINED DESULFURIZATION, DENITRIFICATION AND REDUCTION OF AIR TOXICSUSING ACTIVATED COKE .1. ACTIVITY OF ACTIVATED COKE, Fuel, 76(6), 1997, pp. 549-553
Activated coke (AC) acts both as an adsorbent for SO2 and air toxic ma
terials and as a catalyst for NOx reduction in flue gas treatment at t
emperatures of 100-200 degrees C. AC has a surface area of 150-250 m(2
)g(-1), which is less than that of conventional activated carbons, and
an SO2 adsorption capacity of 60-120 mg g(-1) which is less influence
d by the SO2 adsorption-desorption cycle than that of activated carbon
s. Two types of DeNOx reaction (SCR and non-SCR) can proceed over AC.
Used AC shows 80-85% NOx removal efficiency, which is much greater tha
n that of the fresh material, for SCR-type NOx reduction with NH3 at 1
40 degrees C and space velocity 400 h(-1). Acidic functionality in the
used AC is believed to be an important factor in increasing SCR-type
DeNOx activity. Non-SCR DeNOx proceeds without NH3 addition and may be
attributed to an active N species on the AC surface that reacts with
NOx. NH3 treatment at 400-500 degrees C is effective in activating AC
for the non-SCR reaction. The N species on the AC surface also influen
ces the DeSOx activity. Used AC has a higher adsorption capacity for H
g(0) vapour adsorption than fresh AC, demonstrating the effect of the
surface functionality of AC. (C) 1997 Elsevier Science Ltd.