FGD Additives to Segregate and Sequester Mercury in Solid Byproducts - Final Report

Searcy, K ; Bltyhe, G M ; Steen, W A

关键词: mercury;    flue gas desulfurization;    FGD;    gypsum;    oxidation reduction potential;    ORP;    redox chemistry;   

DOI  :  10.2172/1040032
RP-ID  :  DOE/FE/84682-1
PID  :  OSTI ID: 1040032

学科分类：电力

美国|英语

来源: SciTech Connect

【 摘 要 】

Many mercury control strategies for U.S. coal-fired power generating plants involve co-benefit capture of oxidized mercury from flue gases treated by wet flue gas desulfurization (FGD) systems. For these processes to be effective at overall mercury control, the captured mercury must not be re-emitted to the atmosphere or into surface or ground water. The project sought to identify scrubber additives and FGD operating conditions under which mercury re-emissions would decrease and mercury would remain in the liquor and be blown down from the system in the chloride purge stream. After exiting the FGD system, mercury would react with precipitating agents to form stable solid byproducts and would be removed in a dewatering step. The FGD gypsum solids, free of most of the mercury, could then be disposed or processed for reuse as wallboard or in other beneficial reuse. The project comprised extensive bench-scale FGD scrubber tests in Phases I and II. During Phase II, the approaches developed at the bench scale were tested at the pilot scale. Laboratory wastewater treatment tests measured the performance of precipitating agents in removing mercury from the chloride purge stream. Finally, the economic viability of the approaches tested was evaluated.