In 2011, new US EPA regulations were promulgated to reduce emissions from sewage sludge incinerators (SSI) under section 129 of the Clean Air Act. Because of this action, new SSI mercury emission limits have been enforced since 2016. EnviroCare International (ECI) has designed, fabricated, and tested scrubbers using Sorbent Polymer Composite (SPC) mercury removal materials invented and manufactured by W.L. Gore.
In 2015, ECI installed the first of many MercuryPak Scrubber systems containing SPC modules to remove elemental mercury in the flue gas stream of fluidized bed incinerators (FBI’s). Over the years, ECI has installed nineteen MercuryPak Scrubbers. These scrubbers have been successful and have met their goals of reducing mercury emissions below the regulatory limit of 37 μg/dscm @ 7% O2 for existing source FBI limits.
By implementing improvements to the MercuryPak Scrubber over the past three years, we have observed MercuryPak Scrubbers with modules that have been in use for several years perform as well as scrubbers with brand new modules. Analyzing data from several years of testing shows that the percent reduction of mercury across the module is constant for almost all inlet levels of mercury (these are for nearly constant gas flow rates). Further, we can extrapolate the data to determine how many modules it would take to achieve US EPA new source FBI limits of 1.0 μg/dscm @ 7% O2 for a given inlet concentration and flue gas flow rate. We can also meet country specific mercury emission limits using the same approach.