(74c) Modeling Flare Performance Using Closed-Form and B-Spline Mathematical Functions

Many industries seek to avoid incompliance with the current/upcoming EPA regulations for flare performance and meet the stipulated flare efficiencies along with a smoke-less flaring. To achieve the target performance along with satisfying the EPA regulations, it is necessary to understand the influence of various operating parameters on the overall process. Studying the effect of operating parameters through experiments is tedious, expensive, and time consuming. It would be more cost-effective and organized  to use validated models to guide flare operations. With this objective, mathematical models have been developed to estimate Combustion Efficiency (CE), Destruction Efficiency(DE) and Opacity over a wide range of operating conditions for both steam and air assisted flares . For this purpose, the flare test data with soot emissions for the years 1983 to 2014 (including 1983/1984 EPA, 2010 2010 TCEQ tests, and 2014 Carleton University) were used. Multi-variable parameterized sigmoid /statistical distribution models were developed for the data involving various types of fuels like propylene, propane, natural gas, methane and ethylene. The variables like vent gas Net Heating value at Combustion Zone (NHVcz), Lower flammability limit at Combustion Zone (LFLcz), Combustible concentration at combustion Zone (Ccz) were calculated  and used as inputs along with exit velocity(v)  for the parametric models .  The study was conducted using various  MATLAB^® toolboxes.The developed models were found be in good agreement with the experimental data with a goodness of fit of above 0.9 for both the cases of CE and DE. For the same data, B-form Cubic spline surface modeling has also been done and the results are presented for comparison.  The robust models with high fidelity are envisioned to be used to find conditions that meet specified flare efficiency/opacity and that optimize flare operations in economic terms.