Petrochemistry and Chemical Engineering

Increasing production of gas via fracking technology in the United States has led to the re-emergence of the chemical industry in the US with several new chemical production facilities built in the gulf coast region. Many of these new production facilities include large multi-point ground flares (MPGF). Low-profile MPGFs are very efficient in processing large quantities of flare gas yet pose significant design challenges including elongated flames, high radiation flux to surrounding equipment and associated personnel safety. CFD tools have been used to analyze MPGFs having hundreds of flare burner tips surrounded by specially designed wind fences operated in a chemical plant. This presentation provides an overview of these flares and discusses recent analysis using a transient LES based CFD tool called C3d. This tool includes governing physics to describe soot formation, radiant flux, flame shape and height for an operating industrial scale MPGF. Previous model verification has been conducted for large pool fires and the code has validated for simulating flare performance by comparing measured flame height/shape and radiation flux to simulation results for single burner and three-burner tests when burning ethylene. Comparing transient predictions to steady state results illustrates the need to use transient analysis to capture flame dynamics and associated emissions production and radiation flux during operation of MPGFs in chemical plants. Using the right tool to correctly analyze these complex combustion systems is critical to safe and efficient operation of MPGFs to minimize environmental impact and reduce safety risks.