HIGH-TEMPERATURE SULFUR REMOVAL UNDER FLUIDIZED-BED COMBUSTION CONDITIONS - A CHEMICAL INTERPRETATION

Citation
Sv. Makarytchev et al., HIGH-TEMPERATURE SULFUR REMOVAL UNDER FLUIDIZED-BED COMBUSTION CONDITIONS - A CHEMICAL INTERPRETATION, Chemical Engineering Science, 50(9), 1995, pp. 1401-1407
Citations number
17
Categorie Soggetti
Engineering, Chemical
ISSN journal
00092509
Volume
50
Issue
9
Year of publication
1995
Pages
1401 - 1407
Database
ISI
SICI code
0009-2509(1995)50:9<1401:HSRUFC>2.0.ZU;2-R
Abstract
Theoretical and experimental studies were conducted on coal sulphur re moval under chaotically changing oxidizing and reducing conditions, wh ich occur in the dense zone of bubbling fluidized beds. Experimental d esulphurization trends were analyzed by comparison with multi-species (50 gas-phase, 7 solid-phase species) equilibrium calculations for coa l/steam/sorbent/air system. It was shown, that under fluctuating reduc ing/oxidizing conditions, sulphur capture as CaS in locally reducing z ones increased the sulphur retention level of the sorbent. In experime nts, performed in a 8 cm i.d. bench-scale FBC boiler, effective sulphu r retentions were obtained in the 800-1000 degrees C temperature range . As a chemical interpretation, a time history of sorbent particle cal cination-sulphation is proposed, which leads to the formation of a par ticle structure with a sulphided (CaS) core and a sulphated (CaSO4) sh ell. Full-scale applications are discussed and measures for improving limestone utilization and high-temperature sulphur removal in fluidize d beds are recommended.