Reducing Mercury Emissions from Coal Combustion in the Energy Sector in Russia: Demonstration of Adding Chemical Reagents to Increase Mercury Capture

This document reports a UNEP-supported demonstration to reduce mercury emissions from coal-fired power generation in Russia by injecting oxidizing reagents into the wet particulate scrubber at the Toliatti thermal power plant. Laboratory screening identified potassium permanganate and, preferentially, sodium hypochlorite as effective oxidants for converting elemental mercury to water-soluble forms, while reactions with carbon monoxide were negligible. Building on a closed-loop spray retrofit, pilot tests injected sodium hypochlorite into the scrubber liquor and measured stack mercury with standard sorbent traps, showing total mercury capture increasing from about 20% without chemicals to approximately 55–60% with reagent addition, and near-complete removal of oxidized mercury at modest dosing rates.