Toxic substances form coal combustion--a co prehemsice assessment

Abstract

The Clean Air Act Amendments of 1990 identify a number of hazardous air pollutants (HAPs) as candidates for regulation. Should regulations be imposed on HAP emissions from coal-fired power plants, a sound understanding of the fundamental principles controlling the formation and partitioning of toxic species during coal combustion will be needed. With support from the Federal Energy Technology Center (FETC), the Electric Power Research Institute, and VTT (Finland), Physical Sciences Inc. (PSI) has teamed with researchers from USGS, MIT, the University of Arizona (UA), the University of Kentucky (UKy), the University of Connecticut, and Princeton University to develop a broadly applicable emissions model useful to regulators and utility planners. The new Toxics Partitioning Engineering Model (ToPEM) will be applicable to all combustion conditions including new fuels and coal blends, low-NO combustion systems, x and new power generation plants. Development of ToPEM will be based on PSI's existing Engineering Model for Ash Formation (EMAF). During the last quarter coal analysis was completed on the final program coal, from the Wyodak Seam of the Powder River Basin. Combustion testing continued, including data collected on the self-sustained combustor at UA. Data from PSI and MIT were used to identify the governing mechanisms for trace element vaporization from the program coals. Mercury speciation and measurements were continued. Review of the existing trace element and organics emissions literature was completed. And, model development was begun.iv A description of the work plan for accomplishing these objectives is presented in Section 2.1 of this report.The work discussed in this report highlights the accomplishments of the sixth quarter of this program. These accomplishments include completion of standard coal analysis on the final Phase I program coal. The selective leaching work, to determine the forms of occurrence of various trace elements, was completed for the three bituminous coals. Data from the combustion zone experiments at PSI and MIT were analyzed to explore the observed differences between the two facilities and to determine the dominant mechanisms for trace element vaporization. The review of the existing trace element and organics emissions data from power plants was completed. Two major combustion experiments were completed on the self-sustained reactor at UA. Finally, work was begun to identify the models, and model parameters, required for ToPEM development, and how these models can be incorporated into the existing Engineering Model for Ash Formation (EMAF) Specifically, in the last quarter the trace element concentration analysis was completed for the Wyodak coal. This analysis indicated that the concentrations of trace elements in this coal are within the range of the bituminous coals in this program, with the exception of arsenic. The concentration of this element, and that of chromium, is much lower than was found in the other program coals. The CCSEM analysis of this coal are ...