PRODUCTION OF ACTIVATED CHAR FROM ILLINOIS COAL FOR FLUE-GAS CLEANUP

Activated chars were produced from Illinois coal and tested in several flue gas cleanup applications. High-activity chars that showed excell ent potential for both SO2 and NOx removal were prepared from an Illin ois No. 2 bituminous coal. The SO2 (120 degrees C) and NOx (25 degrees C) removal performance of one char compared favorably with that of a commercial activated carbon (Calgon Centaur). The NOx removal performa nce of the same char at 120 degrees C exceeded that of the Centaur car bon by more than 1 order of magnitude. Novel char preparation methods were developed including oxidation/thermal desorption and hydrogen tre atments, which increased and preserved, respectively, the active sites for SO2 and NOx adsorption. The results of combined SO2/NOx removal t ests, however, suggest that SO2 and NOx compete for similar adsorption sites and SO2 seems to be more strongly adsorbed than NO. A low-activ ity, law-cost char was also developed for cleanup of incinerator flue gas. A three-step method involving coal preoxidation, pyrolysis, and C O2 activation was used to produce the char from Illinois coal. Five hu ndred pounds of the char was tested on a slipstream of flue gas from a commercial incinerator in Germany. The char was effective in removing >97% of the dioxins and furans present in the flue gas; mercury level s were below detectable limits.