Urea Decomposition Chamber

Optimization using CFD and VR


THE PROBLEM

NH3 formation at the top and at the spray nozzles.The Decomposition Chamber inspections indicate significant debris formation in the chamber. The presence of white debris coating the inner liner walls, floor, lances, and the burner swirler indicate that the urea to ammonia conversion initiated, but was unable to complete due to internal temperature gradients below the expected 550 °F. One major point of concern lies within the burner to decomposition chamber roof attachment, where white debris formations repeatedly occur. The debris formation continues to grow which eventually begins to choke out the burner flame. Any debris at this location blocks the chamber from achieving the required temperature for conversion and redirects the burner flame, potentially shifting the flow pattern in the chamber.


THE PROJECT

Countour distribution colored by mass fraction of NH3The goal of this project is to conduct a Computational Fluid Dynamics (CFD) study of a decomposition chamber at NIPSCO for the purpose of optimizing flow distribution and minimizing debris formation. Specifically, the following are main objectives:

  1. To simulate 3D reactions in the decomposition chamber under typical operating conditions. 
  2. To determine and analyze the temperature and flow distribution such that the cause of debris formation can be determined.
  3. To optimize the flow and temperature distribution to minimize the debris formation.

THE OUTCOME

Countour distribution colored by temperatureThe urea decomposition chamber had been well presented by using CFD and Virtual Reality (VR). The simulation results, which were validated against field measurement data, identified excessive recirculation as the cause of the debris formation. As requested by and with the guidance of NIPSCO, parametric study has been conducted with the goal of optimize the flow pattern and temperature distribution by adjusting geometric conditions finding the optimal case with the lowest NH3 concentration with appropriate temperature.


Sponsor: NIPSCO

Urea decomposition project flyer

Download Urea Decomposition Project Flyer