Prediction and measurements of volatile metal partitioning in coal-fired combustion systems

The EPA is required by the 1990 Clean Air Act Amendments to evaluate the emissions of 189 hazardous air pollutants (including trace metals) from electric utilities and determine the levels of control achievable by flue gas scrubbing devices. Testing conducted to date, supported by EPRI and DOE, has indicated that for most metals, high removal efficiencies can be achieved by those facilities which are equipped with good particulate control devices. However certain metals such as mercury, selenium, boron and some radionuclides are not as well controlled with particulate matter control. This paper presents the results of a modeling approach to predict metals behavior of volatile metals in coal-fired combustion boiler furnaces and the degree to which they can be controlled in flue gas clean-up devices. This approach can serve as a guide to help planners, engineers, and facility owners/operators predict the levels of metals emissions from their facilities, and to gain insight on the impact of coal characteristics, operating conditions and APCD design on metals emissions. In this paper the methodology is applied to data generated from one of the DOE sponsored testing programs in order to interpret the data and assess parameters which are likely to influence the behaviormore » of these volatile metals.« less