DEVELOPMENT AND APPLICATION OF AN ACID-RAIN PRECURSOR MODEL FOR PRACTICAL FURNACES

Control of emissions of sulfur (SO2, SO3, H2S) and nitrogen (NO, NO2, N2O, HCN, NH3) pollutants from fossil-fuel-fired furnaces and gasifier s remains a vital worldwide requirement as the utilization of fossil f uels continues to increase. Development and refinement of a predictive model for these acid rain precursors (MARP) has reached the point whe re this technology can contribute to acid rain control. In this paper, model foundations and recent developments are summarized, including f ormation of thermal and fuel NO(x) and sorbent capture of sulfur oxide s. The method includes global formation, capture, and destruction proc esses in turbulent, reacting, particle-laden flows. This submodel has been combined with comprehensive, generalized combustion models (PCGC- 2, PCGC-3) which provide the required local properties for the combust ion or gasification processes. The submodel has been applied to NO(x) formation in a full-scale (85 MW(e)), corner-fired utility boiler, whe re recent in situ NO(x) measurements were made, with variations in coa l feedstock quality (including fuel N percentage) load-level and perce ntage excess air. Predictions are also made for in situ sorbent captur e of sulfur pollutants in both combustion (fuel-lean, SO2), and gasifi cation (fuel-rich, H2S) laboratory-scale reactors. Limitations of MARP are identified and work to improve the submodel is outlined.