OCR Text |
Show 9 Phase llI: Integration Track Task 12: Integration of Chemistry Mechanism with Zero-Dimensional Fluid Mechanics Objective: To integrate the composite chemistry mechanism developed and validated in Tasks 8- 10 with zero-dimensional fluid mechanics models of the burner-furnace flows. Discussion: The composite chemistry mechanism developed and validated in Tasks 8-10 will be integrated with zero-dimensional fluid mechanics models of the burner-furnace flows so that predictions of flame chemistry applicable to petroleum industry process heaters may be made. Initial efforts will be focused on scoping studies to examine the effect of fuel/air ratio, residence time, temperature, and fuel composition on the formation of air toxics. Presently available fluid mechanic models that will be used for this ·purpose include stirred reactors, plug flow reactors, premixed flames, and opposed flow diffusion flames. A two-stage Lagrangian jet diffusion flame model, currently being developed under GRI support, will be adapted to the petroleum industry burner geometries and integrated with the kinetics mechanism. Using these models, the effect of fuel composition on air toxic emissions will be examined, including the effect of varying amounts of hydrogen, propylene, butene, and butane. Conditions under which the formation of air toxics is minimized will be identified. This information will be used to focus and reduce the test matrix for the full-scale burner tests and to develop strategies for potential advanced burner concepts. Hame structure and fluid mechanics measurements of the burners from the assessment track will be incorporated into the models. They will be analyzed so that experimentally observed trends in air toxic emissions can be explained and understood. Strategies will be developed for modifications to existing burners and processes that minimize air toxic formation. Responsibilities: Lawrence Livermore National Laboratory and Sandia National Laboratories, Livermore, are responsible for various parts of this task as indicated below. MilestoneslDeljverables: 12A Recommendations to reduce full-scale emission measurements matrix (Month 6) - LLNL 12B Lagrangian Reactor Model Incorporated (Month 12) - SNL 12C Hame Structure for CDFB Incorporated (Month 15) - SNL 120 Zero-Dimensional CDFB Report (Month 17) - SNL 12E Hame Structure for LDFB Incorporated (Month 19) - SNL 12F Zero-Dimensional LDFB Report (Month 21) - SNL 12G Hame Structure for CPFB Incorporated (Month 27) - SNL 12H Zero-Dimensional CPFB Report (Month 29) - SNL 121 Hame Structure for SPFB Incorporated (Month 31) - SNL 12J Zero-Dimensional SPFB Report (Month 33) - SNL Task 13. Integration of Chemistry Mechanism with Multidimensional Fluid Mechanics Objective: To predict the fluid mechanics and formaldehyde emissions from the burners in the assessment track. Discussion: Fully coupled multidimensional modeling (2-D, currently under development) will be used in the second year of the project to predict the fluid mechanics and formaldehyde emissions from the burners in the assessment track. Additional air toxic species may be added to the calculations as permitted by time and cost constraints. The models will also be used to help define the predict the characteristics of the advanced burner concepts developed in the program. |