Impact of Sulfur Loading on Brominated Biomass Ash on Mercury Capture

• Published in: Energy & fuels Vol. 29; no. 12; pp. 8110 - 8117
• Main Authors: Bisson, Teresa M, Ong, Zong Qian, MacLennan, Aimee, Hu, Yongfeng, Xu, Zhenghe
• Format: Journal Article
• Language: English
• Published: American Chemical Society 17.12.2015
• Subjects: Bromination; Bromine; Carbon; Leaching; Mercury (metal); Sorbents; Sulfur; Uptakes
• ISSN: 0887-0624; 1520-5029
• DOI: 10.1021/acs.energyfuels.5b01213

Brominated carbon injection is a commonly applied technology for capture of mercury in flue gases emitted from coal-fired power plants. However, a previous study has shown leaching potential of mercury (Hg) and bromine (Br) from brominated carbon sorbents, with recommendations to reduce Br concentration in the sorbents. To reduce the Br content required on the sorbent, a strategy of coimpregnation of sulfur and Br was employed in this study. Sulfur (S) loading was found to increase the mercury uptake by the sorbent, with the maximum uptake occurring at a S:Sorbent mass ratio of 1:20. Co-loading of a low concentration of bromine (0.7–0.9%) to the sulfur-loaded sample further improved mercury capture by the sorbent and appeared to have a synergistic effect on Hg removal. Leaching tests confirmed that combining both Br and S onto the sorbent reduced the leaching potential of Br and Hg from the spent sorbent material. In addition, analysis of Hg X-ray absorption spectra (XAS) revealed a mixed Hg–Br, Hg–S, and Hg–C binding environment on the sorbent coimpregnated with bromine and sulfur.