Cost-effective sulfurized sorbents derived from one-step pyrolysis of wood and scrap tire for elemental mercury removal from flue gas. (1st February 2021)

• Record Type: Journal Article
• Authors: Xu, Yang; Luo, Guangqian; Zhang, Qingzhu; Li, Zehua; Zhang, Shibo; Cui, Wei
• Is Part Of: Fuel. Volume 285(2021)
• Publication Date: 2021-02-01
• Subjects: Elemental mercury -- Flue gas -- Co-pyrolysis -- Municipal solid waste -- Sulfur; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2020.119221
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: Cost-effective sulfurized sorbents are developed for Hg 0 removal via one-step pyrolysis. Biomass and scrap tire in municipal solid waste are selected as raw materials. A synergistic effect between two feedstocks occurs during co-pyrolysis process. Sulfurized chars exhibit far better Hg 0 removal performance compared to virgin chars. Organic sulfur/elemental sulfur are responsible for Hg 0 adsorption over sorbents. Abstract: Sulfurized chars derived from one-step pyrolysis of wood and scrap tire are developed as cost-effective sorbents for elemental mercury (Hg 0 ) capture from flue gas. This method can modify chars and enhance their Hg 0 capture capability during samples preparation without additional modification. The sample characterization implies that a synergistic effect between wood and tire occurs during co-pyrolysis. For this reason, the BET surface area and pore volume of sulfurized chars have exceeded the weighted-average sum of biochar and tire-char. The existence forms of sulfur in sulfurized chars are sulfide, organic sulfur (sulfoxide, aliphatic sulfur, and thiophenic)/elemental sulfur and sulfate. At the optimum temperature (140 °C), the sulfurized chars present much higher Hg 0 capture capability compared to biochar and tire-char. The best pyrolysis temperature for preparing sulfurized sorbents is 800 °C, and the optimum wood/tire blending ratio is 50%:50%. The presence of SO2, NO, O2, and HCl can promote mercury capture. The mechanisms responsible for Hg 0 removal are investigated by XPS and Hg-TPD analysis. The results demonstrate that chemisorption dominates the Hg 0 removal process, where organic sulfur/elemental sulfur can serve as active components for Hg 0 oxidization into HgS.