New Granular Sorbent Sulfurization Process for Vapor- and Liquid-Phase Mercury Control

Cost-effective mercury (Hg) (organic forms, elemental and oxidized species) control is needed for incinerator plant flue gas emissions and many aqueous-phase applications. Sulfurizing activated carbons (AC) are known to increase their Hg kinetics and capacity through chemisorption (Hg + S ? HgS). Present commercial sulfur (S) impregnated AC (IAC-S) capacity needs to be improved 10¿100 times to better solve these Hg emission problems. Professional Analytical and Consulting Services (doing business as PACS) has devised a new proprietary process to sulfurize AC. This new process is designed to minimize IAC-S product variability and improve capacity 100 to 1,000-fold. The current commercial products do not work effectively at coal-fired flue gas temperature (140¿C), but this sulfurization IAC-S is expected to satisfy this market application. This new process will be used to infuse S into different sorbents (granular and pelleted AC, and granular clay) to enable increased formation of HgS. PACS¿ new sulfurized sorbents will be compared with current commercial IAC-S products. Physical/chemical characterization methods and Hg sorption performance in the aqueous phase will be tested in the laboratory. Physical/chemical methods include: American Society for Testing and Materials methods, S percent content, BET surface area and pore size distribution analysis, crushing strength evaluation, isotherms, mini-column evaluations, and thermogravimetric analysis. The best performing 50 g batch of new sorbent will be scaled up to a 500 g batch. The larger batch will be compared to the smaller, with physical and chemical properties and performance laboratory-scale testing to remove mercury species from water. This project should lead to a new sorbent that will remove Hg and toxic organic pollutants simultaneously from incinerator flue gas streams and aqueous applications. This new Hg sorbent technology would be located at the end of existing pollutant control devices, as a final polisher. PACS¿ new IAC-S product could be available in multiple forms¿powdered, granular, pellet, and fiber¿to enable engineers many design options in solving different environmental problems. Due to negative-cost raw material, this new sorbent should be the low-cost option. The new process is patentable and fits PACS¿ business mission. In Phase II, PACS would demonstrate a pilot-sized prototype production unit and demonstrate sorbent performance in real-world applications. Sorbents from this production unit would be used to demonstrate commercialization opportunities and initiate the sale of new impregnated IAC-S sorbent.