This is the fourth quarterly report of DOE Contract No. DE-AC22-87PC79864, entitled Modeling of Integrated Environmental Control Systems for Coal-Fired Power Plants.'' This report summarizes accomplishments during the period July 1, 1988 to September 30, 1988. Our efforts during the last quarter focused primarily on the completion, testing and documentation of the NO{sub x}SO process model. The sections below present the details of these developments.

The general goal of this research project is to enhance, and transfer to DOE, a new computer simulation model for analyzing the performance and cost of environmental control systems for coal-fired power plants. Systems utilizing pre-combustion, combustion, or post-combustion control methods, individually or in combination, may be considered. A unique capability of this model is the probabilistic representation of uncertainty in model input parameters. This stochastic simulation capability allows the performance and cost of environmental control systems to be quantified probabilistically, accounting for the interactions among all uncertain process and economic parameters. This method facilitates more rigorous comparisons between conventional and advanced clean coal technologies promising improved cost and/or effectiveness for SO{sub 2} and NO{sub x} removal. Detailed modeling of several pre-combustion and post-combustion processes of interest to DOE/PETC have been selected for analysis as part of this project.