A Low-Cost, High-Temperature Mercury Sorbent for Coal-Fired Power PlantsEPA Contract Number: 68D00263
Title: A Low-Cost, High-Temperature Mercury Sorbent for Coal-Fired Power Plants
Investigators: Nelson, Sid
Small Business: Sorbent Technologies Corporation
EPA Contact: Manager, SBIR Program
Project Period: September 1, 2000 through March 1, 2001
Project Amount: $69,990
RFA: Small Business Innovation Research (SBIR) - Phase I (2000) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , SBIR - Air Pollution , Small Business Innovation Research (SBIR)
Description:The health and environmental effects of trace mercury emissions from coal combustion are increasingly under scrutiny. In response to a recent U.S. Environmental Protection Agency (EPA) Information Collection Request, utilities currently are sampling their coal for mercury and many are sampling their stacks. By the end of the year 2000, the Agency is to decide whether to require mercury reductions from coal-fired power plants. The Phase I objective is to learn how to effectively prepare and use the new mercury sorbents to establish the technology's feasibility, so that a pilot- or full-scale Phase II demonstration can be carried out successfully at a power plant site later.
Unfortunately, if utilities must reduce mercury, it could be very expensive. As the Executive Summary of the EPA's recent Report to Congress on Hazardous Air Pollutants from Utilities stated:
"Regarding potential methods for reducing mercury emissions, the EPA has not identified any demonstrated add-on control technologies currently in use in the United States that effectively remove mercury from utility emissions."
However, an inexpensive material was discovered recently that appears to effectively capture elemental mercury from simulated coal-fired flue gases when injected into ductwork at modest rates. When the powdered sorbent is then removed by the electrostatic precipitator, the mercury is separated from the gas stream as well. Importantly, the new sorbents appear to be effective at high temperatures (300 F to 400 F). This means that expensive gas-cooling or fabric-filter retrofits are not required and that fly ash sales can remain unaffected. Consequently, preliminary estimates of their cost effectiveness suggest that costs are one-tenth of those estimated by the EPA for other technologies.
An existing duct-injection test system will be used in Phase I to parametrically examine the new sorbent's performance, rather than just a simple fixed-bed system, which would not accurately simulate actual sorbent conditions. This project's ambitious performance and cost goals are the demonstration of in-duct elemental mercury removal of 80 percent from a simulated, representative flue gas at 350 F with an estimated cost of less than $3,000 per-lb-of-Hg removed, one-tenth that of current technologies.