406 Dirksen EPW Hearing Room
Dr. Richard Bucher
W.L. Gore and Associates
Gore is a leading company in the field of advanced materials that provide creative solutions to long-standing problems. We believe that a new mercury capture system we have developed, and that has recently been tested at the EPA, may well offer dramatic improvements in the effectiveness, efficiency and cost of mercury capture from flue gas. We are very excited by this development, as an improvement of this kind in mercury control could greatly contribute both to the long-term sustainability of power generation from coal, and to the health of all Americans.
I greatly appreciate the opportunity to testify today. My employer, W.L. Gore & Associates, is best known as the maker of GORE-TEX® fabrics. Many of you may own or use GORE-TEX® garments for hiking, hunting or running. Gore has been using the same high-performance polymer membrane that makes our fabrics waterproof, windproof and breathable in many other applications for more than 30 years. We manufacture a wide range of electronic, medical and industrial materials and devices. Of main interest to us today is the application of the GORE-TEX® membrane, and related membranes, to the field of industrial filtration.
Gore has built a reputation since the 1970s as a leading supplier of high-performance filter bags to the energy industry, cement kilns, chemical and metals production facilities, waste incinerators and other industrial applications. Beginning in the 1990s, Gore scientists and engineers have discovered and developed a series of radical improvements to our bags through embedding additional materials and properties into the structure that makes the bags work. These advances have led to new applications for capturing over 99.99% of fine particulate, for catalytically destroying over 99% of dioxins and furans, and most recently for capturing over 90% of mercury in flue gas streams. The result is a cleaner, safer, healthier environment and more sustainable industry.
Our invention in the area of mercury capture has moved well beyond the lab bench and shows dramatic promise for the future. Our product relies on the same basic technique as the best current technology – using activated carbon to capture mercury – but in a way that is up to two orders or roughly 100 times more effective -- and that has dramatic positive implications for the waste handling and cost features of our solution.
Current technologies to control mercury emissions from coal fired power plants include activated carbon injection, wet scrubber technology, selective catalytic reduction (SCR) technology, combinations of these, as well as a host of other potential options. The United States Environmental Protection Agency’s “Mercury Study Report to Congress” from December 1997 presents an exhaustive review of the technological options and their associated financial impact. This report indicates that active carbon injection represents the greatest potential for the lowest cost, most technically feasible solution.
Unfortunately, activated carbon injection has significant drawbacks that make the technology incompatible with some coal fired power facilities and fiscally prohibitive to others. A primary drawback of activated carbon injection is contamination of the facility’s fly ash. Not only does the presence of the carbon render the fly ash un-salable, but also the presence of mercury has the potential to require the fly ash to be classified as a hazardous waste and be disposed of accordingly. Additionally, the literature remains inconclusive regarding the ability of activated carbon to consistently control elemental mercury emissions, making this technology potentially incompatible with many existing facilities burning lignite and Powder River Basin (PRB) coals. Activated carbon injection also requires a coal fired power plant to purchase, store, inject and dispose of a large volume of material. This has the secondary impact of requiring additional footprint and capital expenditures related to the necessary equipment, and also further burdens the particulate capture equipment with additional dust loading and pressure drop. Wet scrubber technology is incapable of controlling elemental mercury emissions, and SCR (selective catalytic reduction) technology is prohibitively expensive when employed solely for mercury control.
The lack of a financially and technically compelling alternative for mercury emissions control from coal fired power plants led W.L. Gore and Associates, Inc. to create a technology project focused on investigating the feasibility of efficiently trapping and immobilizing gaseous mercury compounds from flue-gas streams using a reactive filter system. The progress to date of this work is summarized in this testimony.
Initial work at Gore focused on developing a wide variety of reactive mercury trapping formulations. A bench-top screening experiment was then conducted to identify formulations with the best opportunity for long-term success. To add credibility and confidence to this study,
all testing was performed at the EPA’s research facility in Research Triangle Park, North Carolina. The mercury test reactor utilized allowed for control of inlet concentrations of mercury, SO2, NOx, H20 and O2. Analysis methods included both continuous mercury monitoring and the widely accepted standard Ontario Hydro test procedure. To accelerate the testing an inlet mercury level of 1 PPM Hg, far in excess of typical coal fired power plant emissions, was selected. To further challenge the samples, testing was conducted at 185°C (365°F), significantly above typical baghouse conditions.
The performance of the highly active samples were then compared with state of the art mercury absorbent technology as reported in the literature. Most comparison materials represented treated and untreated activated carbons. A summary of the data is shown in figure 1, with traditional activated carbon capacities shown in blue (as reported in the literature) and capacities for Gore technology shown in maroon. As illustrated the Gore technology shows a dramatic increase in the adsorption capacity in comparison to conventional materials.
Figure 1: Mercury adsorption capacity comparison of conventional technologies with Gore technology.
The key to our technology lies in this increased capacity to capture and hold mercury. This advance has the potential to allow the coal fired power industry to move the function of mercury control from a consumable material, as with traditional activated carbon injection, to a system component, such as a filter bag or a filter bag insert. Retrofitting a facility with a fabric filter bag- house already in place can be as easy as dropping mercury trapping inserts into the existing filters, requiring no additional system infrastructure or space. Most significantly this approach does not contaminate the fly ash with mercury-laden activated carbon, allowing facilities to continue to sell, as opposed to landfill, this valuable by-product of the coal fired power industry. Finally, our technology is completely passive in nature. Once installed it is always operating, continuously protecting the air we breathe, and does not require additional operators, maintenance or monitoring.
Full size samples have been produced to test mechanical performance and integrity in a full-scale commercial facility. Figure 2 shows a photograph of a full size Gore-TexÒ filter bag with a mercury capture insert. Two such prototypes have been installed on a commercial incineration facility and have been successfully operational since November 2002. This test continues to run to demonstrate long term mechanical integrity.
Figure 2: Filter bag, mercury capture insert system.
As indicated, the development of our technology has progressed from the laboratory/bench scale phase to pilot testing. Our most significant testing to date was conducted at the EPA on their pilot scale coal combustion unit. The seven-week trial, with 24-hour operation, was designed to test the long-term viability of the technology under a variety of conditions, burning both Powder River Basin (PRB) coal and Lignite coal. Coal burning trial results, illustrated in Figure 3, indicate mercury capture rates consistently in excess of 90%.
Figure 3: Mercury test results before and after the Gore mercury capture system. Tests conducted with PRB Coal, Lignite Coal and Mercury doped Nature Gas (to simulate high mercury inlet levels)
These results, assuming further successful field verification, would allow coal burning facilities to easily comply with the most stringent regulations set forth in the CLEAR SKIES Act of 2003, and the CLEAN AIR PLANNING Act of 2003, and would even approach the control levels required in the CLEAN POWER Act of 2003.
As a private company serving the air pollution control industry for over 30 years, we at W.L. Gore & Associates clearly realize that even the most advanced technology must provide our customers an economic advantage. Our mercury technology is being designed to provide the benefits stated above, while potentially costing considerably less than activated carbon injection. The EPA research and development report titled “Performance and Cost of Mercury Emission Control Technology Applications on Electric Utility Boilers” identifies carbon injection as the most cost-effective approach available to date for utilities without existing scrubbers and SCR systems. For example activated carbon injection for a 110 MW facility is projected to cost approximately $700,000 per year. When the lost revenue of un-salable fly ash is added, these numbers inflate to a range from $1.1MM to $1.5MM per year. Current estimates indicate our technology could be 38% to 83% lower than these values, making our approach both easier to implement, and more cost effective.
Although we have not begun marketing this technology to the coal fired power industry, our interactions with prospective customers have been nothing short of extremely encouraging. Owners and operators of our nations coal fired power plants have expressed enthusiastic support for our concept, citing the ease of implementation, minimal impact on system performance, and most of all the preservation of fly ash value which is so critical to their bottom line. Indeed initial support has been so strong that most facilities we’ve interacted with have eagerly volunteered as locations for future field-testing.
Once again, I appreciate the opportunity to testify before you today regarding the important issue of mercury emissions control. W.L. Gore & Associates remains committed to developing innovative, economically feasible technologies to address our nation’s air quality challenges. We look forward to continuing to work with the Committee, the EPA and the coal fired power industry to make this technology a commercial reality.
Thank you again for allowing me to testify, and I’m pleased to answer any questions you may have for me.
GORE-TEX is a Registered Trademark of W.L. Gore & Associates, Inc.