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Show American Flame Research Committee 1995 Fall International Symposium Monterey, CA, October 15-18, 1995 Chemical Kinetics Modeling of Air Toxics and NOx in a Turbulent Diffusion Flame Burner Andrew E. Lutz and James E. Broadwell* Sandia National Laboratories Livermore, CA 94551 ABSTRACT A one-dimensional model for chemical kinetics in turbulent nonpremixed jet flames is used to study emissions of NOx and air toxics from a conventional diffusion-flame burner, using a fuel mixture intended to duplicate refinery fuel gas. The model predicts that NOx emissions increase with hydrogen content in the fuel, in rough agreement with measurements. Air toxic species generated in the fuel-rich region of the solution are completely oxidized as further entrainment takes the mixture through stoichiometric conditions to excess air. INTRODUCTION Concerns regarding the ability of refineries to meet requirements of the 1990 Clean Air Act have prompted a consortium of refineries to request studies of air toxic emissions from burners used as process heaters. Experiments conducted at the Burner Engineering Research Laboratory (BERL) at Sandia National Laboratories measured NO x and air toxic emissions for a conventional diffusion flame burner at a variety of operating conditions. As part of a collaborative research program between the Department of Energy and the Petroleum Environmental Research Forum, the chemical kinetics of air toxic formation are being developed. This paper describes the application of a chemical kinetic model for turbulent jet flames to the burner under investigation. MODEL DESCRIPTION The Two-Stage Lagrangian model was developed to describe chemical reactions in turbulent jets. It is based on the experimental observations of the structure of reacting layers in turbulent flames. The model was originally developed for the shear layer by Broadwell and Breidenthal1 and Broadwell and Mungal.2 ,3 The initial model development for the jet is given in Broadwe1l4 ,5 and the application to an investigation of NOx generated in hydrogen and methane flames in Tyson et al.6 Further developments are reported in Lutz et a(,,8 and Broadwell and Lutz.9 * Consultant { \ t. 1 |