About Enviroscrub

EnviroScrub’s 97% Removal Rate for Oxidized Mercury Verified by Joint Testing with DOE, EERC and DTE Energy.

The U.S. Department of Energy (DOE), the Energy & Environmental Research Center (EERC), and DTE Energy sponsored research activities at DTE Energy’s River Rouge Plant to collect the information and measurements necessary to evaluate the effectiveness of EnviroScrub’s multi-pollutant control technology on speciated mercury emissions. Testing was conducted on DTE Energy’s Unit 3, which burns a blend of subbituminous Powder River Basin (PRB) coal and eastern bituminous coal. During testing, a flue gas slipstream was transferred to the EnviroScrub pilot scrubber via temporary 10-inch piping penetrating the Unit 3 duct downstream of the electrostatic precipitator (ESP). Flue gas entering the pilot scrubber passed through an air-to-air heat exchanger and then into the baghouse reaction chamber. Pollutants were removed as they passed through the reaction chamber baghouse and came into contact with EnviroScrub’s Pahlmanite™ sorbent.

Mercury Removal

Sampling at River Rouge was conducted 10-13 June, 2003. During that time period, mercury measurements were conducted at the inlet and outlet piping of the EnviroScrub pilot scrubber using both the EPA-approved Ontario Hydro (OH) method as well as mercury semicontinuous emission monitors (Hg SCEMs). Concurrent with the inlet and outlet mercury test runs, concentrations of O₂, NO_x, SO₂, and CO were measured using the EnviroScrub CEMS contained within the pilot scrubber control room. A single CEMS was configured with both inlet and outlet sample conditioning systems, which enabled the CEMS to alternate between the pilot scrubber inlet and outlet ducts.

Results indicate that up to 80% of the total mercury and up to 97% of oxidized mercury was removed using the Pahlman™ Process pilot scrubber. The reactive nature of the fly ash from Unit 3 resulted in substantial mercury removal across the ESP, leaving approximately 1 µg/Nm³ at the ESP outlet and slipstream immediately prior to EnviroScrub’s pilot scrubber. While removal of mercury at inlet concentrations below 1 µg/Nm³ is difficult, the Pahlman™ process demonstrated 70% to 80% removal of total mercury and 96% to 97% of oxidized (Hg²⁺) removal across the reaction chamber’s filter cake. Further, this mercury removal was achieved with the simultaneous removal of near 100% SO₂ and up to 98.3% NO_x.

Mercury Removal Chart

Diagram of the EnviroScrub pilot unit system and slipstream piping at DTE Energy’s River Rouge Power Plant.

Enviroscrub's Pahlman^TM Process Technology Successfully Enters Mercury Removal Market -- Combined Elemental and Oxidized Mercury Removal Rates of 67%.

To further evaluate the multi-pollutant aspects of Enviroscrub's proprietary Pahlman^TM Process technology, G.E. Mostardi Platt, a division of G.E. Energy & Industrial Services, Inc., was contracted to perform mercury (Hg) emissions removal efficiency testing on Enviroscrub's mobile Pahlman^TM Process plant. Testing was conducted on December 10-12, 2001 at Minnesota Power's Boswell Energy Center located in Cohasset, Minnesota. A slipstream of approximately 1000 dry standard cubic feet per minute (DSCFM) was extracted from the reheat gas stream, downstream of the Unit 4 electro-static precipitator (ESP). Minnesota Power's Boswell Unit 4 boiler is a 570 MW tangentially-fired coal boiler burning low sulfur western coal.

The test program consisted of triplicate US EPA Method 29 sample trains and a method blank conducted simultaneously on both the inlet and outlet ducts of Enviroscrub's Pahlman^TM Process pilot scrubber. The results show mercury removal rates up to 67%, for combined elemental and oxidized forms of mercury. "We are excited with these initial results", commented Charles Hammel, Enviroscrub's Chief Technology Officer, "if we are able to capture high rates of the more difficult elemental and oxidized forms of mercury, we feel our total mercury removal rates will be among the industry's best. A baghouse is a key component of our system, so we expect to capture virtually all of the particulate mercury present in the emissions." With these outstanding initial results, Enviroscrub is poised to bring to market not only high removal rates for criteria pollutants such as NO_x and SO₂, but also to establish itself as the world's leading multi-pollutant emissions control technology provider.

Click here to see GE Mostardi Platt's Mercury Report - February 2002.
Click here to see EERC's Mercury Removal Report - August 2003.