REUSE OF PARTIALLY SULPHATED CFBC ASH AS SO2 SORBENT
It is not uncommon for ashes produced from fluidized bed combustion (FBC) technology, including circulating FBC (CFBC), to contain 20-30％ of unreacted CaO following limestone addition to remove SO2 in situ. This paper presents the results of reactivating partially sulphated CFBC ash (both bed ash and fly ash) with liquid water and steam. The hydrated ashes were subsequently re-sulphated in a thermogravimetric analyzer (TGA) with simulated flue gas. The TGA results show that, while liquid water and steam successfully hydrate and reactivate the unreacted CaO in the bed ash, ashes so treated sulphated to widely different extents. Attempts to reactivate fly ash with hydration have failed, although fly ash by itself is extremely reactive. A pilot-scale mini-CFBC was also used to evaluate the results of reactivation on the bed ash by hydration with liquid water and mixing of inorganic salt (Na2CO3) in the form of either powder or solution. When the treated ash is re-injected into the combustor with the fuel, the effect on SO2 removal efficiency is negligible if Na2CO3 is added as powder. Doping with aqueous solution results in enhancing SO2 removal, however, the extent was lower than the level achieved if only water hydration is employed. Increasing the amount of water (from 10％ to 30％) to reactivate the ash does not improve the sulphur capture capacity. Overall, this study suggests that the most practical way for re-use of the partially sulphated ash is reactivation by water.
FBC CFBC ash reactivation hydration sulphation
Yinghai WU Marianna Nobili Edward J.Anthony Lufei JIA
CANMET Energy Technology Centre-Ottawa (CETC-O), Ottawa, Ontario, Canada Department of Chemical Engineering, University of Potenza, Italy
国际会议
第六届煤燃烧国际会议(The 6th International Symposium on Coal Combustion)
武汉
英文
483-490
2007-12-01（万方平台首次上网日期，不代表论文的发表时间）