Richard A. Hargis

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Based on the available evidence of health effects, the U.S. Environmental Protection Agency (EPA) has been evaluating the need to regulate mercury releases to the environment. In response to the congressional mandates in The 1990 Clean Air Act Amendments (CAAA), the EPA has issued the Mercury Study Report and the Study of Hazardous Air Pollutant Emissions(More)
Activated carbon injection for Hg control in a 500-lb/hr pilot-scale coal-fired furnace equipped with a fabric filter for particulate control was evaluated at different operating conditions. The pilot-scale tests showed that Hg removal was improved at lower temperatures and higher C/Hg ratios. The two-stage mathematical model developed to describe Hg(More)
The Thief Process is a cost-effective variation to activated carbon injection (ACI) for removal of mercury from flue gas. In this scheme, partially combusted coal from the furnace of a pulverized coal power generation plant is extracted by a lance and then re-injected into the ductwork downstream of the air preheater. Recent results on a 500-lb/h(More)
The Thief Process is a mercury removal process that may be applicable to a broad range of pulverized coal-fired combustion systems. This is one of several sorbent injection technologies under development by the U.S. Department of Energy for capturing mercury from coal-fired electric utility boilers. A unique feature of the Thief Process involves the(More)
A two-stage mathematical model for Hg removal using powdered activated carbon injection upstream of a baghouse filter was developed, with the first stage accounting for removal in the ductwork and the second stage accounting for additional removal caused by the retention of carbon particles on the filter. The model shows that removal in the ductwork is(More)
Four mercury oxidation catalysts were tested in a packed bed reactor in the presence of flue gas generated by the NETL 500 lb/h coal combustor. The four catalysts tested were Ir, Ir/HCl, Darco FGD activated carbon, and Thief/HCl. The Thief/HCl and Darco converted the highest percentage of the inlet mercury; however, the high conversion in these experiments(More)
A mathematical model based on simple cake filtration theory was coupled to a previously developed two-stage mathematical model for mercury (Hg) removal using powdered activated carbon injection upstream of a baghouse filter. Values of the average permeability of the filter cake and the filter resistance extracted from the model were 4.4 x 10(-13) m2 and 2.5(More)
A two-stage mathematical model for mercury removal using powdered activated carbon injection upstream of a baghouse filter was developed, with the first stage accounting for removal in the ductwork and the second stage accounting for additional removal due to the retention of carbon particles on the filter. This model incorporates key mass transfer and(More)
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