Uses at Coal Fired Power Plants

MATS Compliance for Mercury Emissions in wet FGD Units

  • Provides a fast-acting mercury control option during unit start-up, SCR bypass, ORP excursions, or other events that may trigger higher Hg stack emissions. 
  • Lowers total stack mercury emissions by up to 95%. 
  • Requires less mercury (Hg) oxidation than other wet scrubber additives (WSA) to meet MATS compliance. 
  • Effective over a wider pH (4.5 to 7.0) and ORP (-200 to +600mV) range than traditional wet scrubber additives (WSA).

Dissolved Metals Removal from Scrubber Effluent

Redox 5545 was injected into a forced oxidation wet FGD scrubber for a period of 30 days at 10 gallons per hour to evaluate the effect of stack mercury control and dissolved metals removal. The results showed:


  • Stack mercury (Hg) was well below the plants MATS compliance goal of 1.2 Lbs./TBtu. 
  • A removal of dissolved mercury (Hg) by 93%.
  • A removal of selenite by 93%.
  • A removal of arsenic (As) by 50%.

ORP Control in wet FGD Units

The oxidation-reduction potential (ORP) is highly related to Hg re-emission in wet flue gas desulfurization (WFGD) systems in coal-fired power plants. An ORP in excess of +250 has shown to induce mercury re-emission. Redox’s products have been used in forced oxidation wet FGD units to control ORP resulting in lowering stack mercury (Hg) emissions.


An example of this would be a 1,300 MW station, burning bituminous coal, with a forced oxidation FGD unit that was experiencing mercury re-emission  with an ORP of +650. The station injected 1 tote (300 gallons) of Redox 5545 into the  absorber sump and within 15 minutes the ORP lowered to +200 with stack mercury lowering from 1.7 to 0.50 lbs./TBtu.

Bromide Removal from Scrubber Effluent

In the above referenced 30 day dissolved metals trial, the bromide concentrations were reduced by over 50% with a consistent injection of Redox 5545.