Grantee Research Project Results

Final Report: Impregnated Clay Sorbents for Mercury Removal From Flue Gas

EPA Contract Number: 68D03011
Title: Impregnated Clay Sorbents for Mercury Removal From Flue Gas
Investigators: Lovell, John S.
Small Business: ADA Technologies Inc.
EPA Contact: Richards, April
Phase: I
Project Period: April 1, 2003 through September 1, 2003
Project Amount: $69,984
RFA: Small Business Innovation Research (SBIR) - Phase I (2003) RFA Text |  Recipients Lists
Research Category: SBIR - Air Pollution , Small Business Innovation Research (SBIR) , Air Quality and Air Toxics

Description:

ADA Technologies, Inc. (ADA) identified and began to evaluate a new class of inexpensive sorbents that potentially could solve the problem of mercury control in flue gases at an acceptable cost to the utility industry, as well as provide enhanced protection to the U.S. population. Without support from the U.S. Environmental Protection Agency, it is unlikely that these promising sorbents would have been discovered. The Phase I research project had three principal objectives: (1) investigate mercury sorbents, based on silicates impregnated using alternative amendments, and an alternative preparation chemistry that was expected to offer significant improvements in the sorbent performance and ease manufacturing; (2) build and test an in-flight test rig to measure the performance of mercury sorbents in dynamic flow conditions, including modeling the sorbent performance versus carbon; and (3) perform the initial calculations to project the potential costs of the sorbents.

Summary/Accomplishments (Outputs/Outcomes):

All of the objectives were met or exceeded. The project investigated two different silicate substrates, two different sources of amendment ions at a variety of concentrations, and two alternative final chemical amendment steps. ADA was highly successful in preparing amended silicate sorbents with mercury capacities of up to 12 mg/gm in static bed testing. These capacities exceed the published capacities of activated carbon by approximately an order of magnitude, as well as exceed the mercury capacities of previous amended silicate sorbents identified by ADA in other projects by at least a factor of two.

The in-flight test rig proved to be more difficult to construct than expected, but by the end of the project, it produced excellent data and good comparative performances of various sorbents. The new sorbents identified in this project outperformed both the earlier sorbents developed by ADA and flue gas desulfurization activated carbon in identical head-to-head dynamic tests. Excellent mercury control has been observed at injection rates as low as the equivalent of 0.8 lb/MMACF in a full-scale power plant.

This test rig is an invaluable tool that will be used in ADA's sorbent-development activities. Recently, ADA received notice of an award from the U.S. Department of Energy for a full-scale demonstration of the Amended Silicate™ technology at a 75-MW facility operated by Cinergy Corporation. This full-scale demonstration will require ADA and our partner, CH2MHill, to manufacture 70 tons of sorbent material. The in-flight test facility will be invaluable as a direct quality control tester in allowing for rapid evaluation of sorbent performance as the sorbents are made.

Conclusions:

The new silicate-based sorbents identified in this Phase I research project have the potential to be less expensive than carbon on a per-pound basis and have 3 to 10 times carbon's capacity for mercury in static tests. Successful completion of the commercialization of this sorbent clearly has the potential to save the power generation industry and the U.S. public hundreds of millions of dollars per year.

Supplemental Keywords:

clay sorbents, mercury removal, flue gas, utility industry, silicate, chemistry, activated carbon, in-flight test rig, power plant, air pollution, small business, SBIR., RFA, Air, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, INDUSTRY, Industrial Processes, Engineering, Air Quality, Environmental Chemistry, Engineering, Chemistry, & Physics, Analytical Chemistry, Monitoring/Modeling, Atmospheric Sciences, Environmental Engineering, Environmental Monitoring, trace element speciation, air sampling, combustion gas streams, field portable monitoring, mercury sorbents, field portable systems, flue gas monitor, trace gases, emission control, emissions monitoring, combustion, combustion gases, ambient emissions, field monitoring, mercury emissions, mercury recovery

SBIR Phase II:

Chemically Impregnated Sorbents for Mercury Control