DRG was engaged to conduct a comprehensive stress analysis for three sulphur recovery burners, in accordance with ASME VIII Division 1 of the Boiler and Pressure Vessel Code. This analysis included both Division 1 calculations and Finite Element Analysis (FEA) to evaluate the impact of loads at the junctions of the nozzles. Each burner assembly features a vessel with an air inlet nozzle, a head, and a large-diameter nozzle attached to the head. This large nozzle is sealed with a blind flange through which a gun pipe extends, incorporating several inlet nozzles for fuel and/or acid gas intake. The burner is designed to operate at temperatures up to 350°C and internal pressures of 5 barg, where the fuel gas combusts to produce a large flame for additional waste gas burning in the connected chamber.
Analysis
The preliminary designs provided by the client were scrutinized according to the ASME VIII Division 1 Boiler and Pressure Vessel Code. Loads on various inlet nozzles were transformed into statically-equivalent loads for critical areas, including the connection flanges joining the gun to the burner and the burner to the chamber. Flanges were then selected or sized based on these equivalent pressure loads.
To evaluate the stress at transition points between different burner components, a Finite Element Model (FEM) was developed. These interfaces are critical due to potential stress concentrations.
Multiple nozzle loads were assessed to evaluate the integrity of the main connection flanges of the burners.
Results
The analysis according to Division 1 revealed that several components required modifications from the initial designs across all three burners. Adjustments were necessary to meet code compliance, primarily involving increases in wall thickness.
