Wet Scrubber Additive

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 up to 95%. 
  • Requires less mercury (Hg) oxidation than other wet scrubber additives 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.

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:

To evaluate the effect on stack mercury control and dissolved metals removal in afforded oxidation wet FGD scrubber, Redox 5545 was injected into the scrubber at a rate of 10 gallons per hour for 30 days.  In addition to stack mercury (Hg) remaining well below the MATS compliance goal of 1. Lbs/TBtu, concentrations of dissolved mercury were also lowered by 93%, selenite (93%), and arsenic (50%) in the scrubber slurry blowdown.

ORP Control in wet FGD Units

The oxidation-reduction potential (ORP) is highly correlated to Hg re-emission in wet flue gas desulfurization (wFGD) systems in coal-fired power plants. An ORP in excess of +250mV has been shown to promote mercury re-emission. Redox’s products have been used in forced oxidation wFGD 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 +650mV. The station injected one tote (300 gallons) of Redox 5545 into the  absorber sump and within 15 minutes, ORP was lowered to +200 mV and stack mercury was reduced 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.
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