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EVALUATION OF TRACE ELEMENT RELEASE FROM FLUIDIZED-BED COMBUSTION SYSTEMS
Citation:
Alvin, M., E. O'Neill, L. Yannopoulos, AND D. Keairns. EVALUATION OF TRACE ELEMENT RELEASE FROM FLUIDIZED-BED COMBUSTION SYSTEMS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/7-78/050.
Description:
The report gives results of an investigation of four trace elements: lead, beryllium, mercury, and fluorine. The chemical fate of minor and trace elements is important in assessing the environmental impact of the fluidized-bed combustion (FBC) process and, for certain elements, in determining the potential for deposits or corrosion in process equipment. Equilibrium product distributions for these elements, at operating conditions corresponding to atmospheric and pressurized FBC systems, are projected on the basis of thermodynamic calculations. Results show which elements are likely to be volatilized in the high-temperature zone of the combustor and which are likely to condense on cooling the gases. The projections are compared with available experimental plant data. Alternatives for continuously monitoring the release of the four toxic trace elements in the laboratory were also investigated. The thermodynamic analysis shows that essentially all the lead, mercury, fluorine, and beryllium can be volatilized in the FB combustor. Partial beryllium and fluorine condensation in the form of clay and alkali compounds will occur. Lead condensation is affected by the chlorine available. These thermodynamic projections provide a basis for experimental and monitoring studies. Initial plant data generally confirm the projections.