(2c) Ultra Low NOx Burner Testing and Field Validation for an Ethylene Furnace Retrofit Application

The Equistar Chemicals, LP, Corpus Christi revamp project goals were to increase furnace capacity while increasing the plant ethylene capacity by 50% using ethane as incremental feed.  The project targeted fifteen existing Technip cracking furnaces of three different designs.  Each of the original designs was a combination of floor fired and wall fired with wall burners.  Due to the increased cracking of ethane, the new fuel composition was expected to contain 70 mole% hydrogen.  In order to meet the heat flux profile target, the majority of the duty will come from hearth firing.  In order to meet the challenging NOx emissions requirements of this project, some of the fuel for the wall burners will be injected through the patented Remote Fuel Staging (RFS) injectors.  In addition to a narrow firebox width compared to modern furnaces, some concern was generated by the presence of a substantial shield wall between the burners and the coils. The height and location of the shield wall in combination with the narrow firebox could have an impact on the floor burner recirculation patterns and NOx emissions.  Extensive burner testing and CFD modeling was carried out to optimize burner design and placement, ensuring that flame shape and heat flux profile targets were met while minimizing NOx emissions. This paper presents and compares CFD and burner test results with field data.