Development of Speciated Industrial Flare Emission Inventories for Air Quality Modeling in Texas

General Requirements This project is a secondary data project. A secondary data project involves the gathering and /or use of existing environmental data for purposes other than those for which they were originally collected. This document is based on EPA's National Risk Management Research Laboratory (NRMRL) QAPP for secondary data project and satisfies a Category III level of QA. Executive Summary In this project, computational fluid dynamics (CFD) methods based on CHEMKIN-CFD and FLUENT are used to model low-Btu, low-flow rate propylene/TNG/nitrogen flare tests conducted during September 2010 in the John Zink test facility, Tulsa, Oklahoma. The flare test campaign was the focus of the TCEQ Comprehensive Flare Study Project (PGA No. 582-8-862-45-FY09-04) in which plume measurements using both remote sensing and direct extraction were carried out to determine flare efficiencies and emissions of regulated and photo-chemically important pollution species for both air-assisted and steam-assisted flares under open-air conditions. This project (1) models and predicts the performance of Tulsa testing flares at low heating value and low jet velocity conditions using the CFD approach, and (2) further compares with the measured flare performance data. This modeling tool has the potential to help TCEQ's ongoing evaluation on flare emissions and to serve as a basis for a future State Implementation Plan (SIP) revision and the effect of these relations on flare performance was studied. The 50-species combustion mechanism was reduced from the combined GRI and USC mechanisms with the goal of allowing NOx formation and handling light hydrocarbon combustion. This optimized Lamar mechanism has been validated against methane, ethylene, and propylene experimental data. Further, NO 2 was added to the existing mechanism and was shown in good agreement with the full mechanism. FLUENT models (species, turbulence-chemistry, viscous flow and Numerical algorithms), model parameters, and boundary conditions have been selected. The main operating, design, and meteorological data of the flare test campaign were provided by the University of Texas (UT) including Combustion Efficiency (CE), Destruction and Removal Efficiencies (DRE). Both Probability Density Function (PDF) and Eddy Dissipation Concept (EDC) turbulence-chemistry interaction approaches have been adopted to run Tulsa flare test cases. Twelve air-assisted flare test cases and nine steam-assisted flare test case have been run and compared with the measured DRE/CE data. In general, the EDC model under-predicts DRE by 6% to 19% with an average of 12%. It under-predicts CE by 12% to 39% with an average of 25%. Comparing the …